Living with our hazards
Most of us who live in New Zealand think it’s the most beautiful place on Earth (even if we might be a bit biased). But as it has been throughout New Zealand’s history - with natural beauty comes natural hazards.
Mountains and hills can signify earthquake fault lines or be at risk for slips and landslides. Rivers can flood through entire towns. Our coastline often bears the brunt of storm surges and inundation. On top of this, we also need to consider any man made hazards that exist in our area.
It’s part of Council’s role to research and collect new information on all these hazards so we can help in appropriately managing the risk to people and property. Council is required by law not only to investigate hazards, but to make the research available to anyone who is affected or interested.
Nelson City Council has had recent expert advice about narrowing down the location of earthquake fault lines that may affect our city and there has also been work done to identify areas that could be affected by a major Maitai River flood. Recent research has also identified areas where liquefaction is possible in the event of a major earthquake, and areas where past or present land use could result in potentially contaminated land.
It’s important to say that the actual risk from hazards doesn't change as a result of new information. Homes are no more likely to be affected than they were last week. Council wants to share new information with the community so we can all work together on being prepared. The following information is quite general so please contact us if you have questions specific to your property.
It is important to note, there is potential for flooding, liquefaction or ground contamination to happen in other areas around Nelson too. This information simply relates to the areas that Council has researched so far.
Flooding around the Maitai River is one of our most common and well understood natural hazards. The river has flooded in the past and may do so again. Council has invested in new research to get a clearer picture of whether the scale, nature and frequency of flooding is changing. This research is useful for planning for new buildings or upgrading Council infrastructure with the aim of reducing the possibility of damage in flood prone areas.
Most owners of affected properties will already know they’re in a flood prone area but this new information improves our ability to make predictions about how flooding could change between now and 2110. The report is available in the "Downloads" section below.
Following the damage caused in the Canterbury quakes, Council opted to put some resources into assessing the likelihood of ground liquefaction following an earthquake in our area.
A geological assessment of our region suggested the Tahunanui area could be susceptible to liquefaction so Council contracted Tonkin and Taylor to run some tests. The preliminary assessment and the subsequent detailed report are available under the downloads section below.
While the results are still preliminary at this stage, the evidence suggests that some areas in Tahunanui may indeed be subject to liquefaction following a significant quake. However the scale of the liquefaction and the possible effects on homes and services is very difficult to predict.
What will it mean for affected properties?
Any new builds or developments in the affected areas could be required to do further testing and/or incorprate advice from MBIE (visit the website here) in their foundation and building design as part of the consent process. If the house is already built, nothing needs to change but a note will be added to the Council property file so any future owners are made aware of the liquefaction risk. Nelson City Council doesn’t have any information on whether this will have any effect on insuring your house. You’ll need to discuss that with your insurance company.
Fault Hazard Overlay
The fault hazard overlay will be reviewed as part of the Nelson Plan review scheduled for 2014-2017. You can see more information on the NRMP fault hazard overlay and the updated fault hazard corridor here.
Historic or current land use and potential soil contamination - HAIL sites in Nelson
The Hazardous Activities and Industries List (HAIL) is a compilation of activities and industries that are considered likely to cause land contamination resulting from hazardous substance use, storage or disposal. The HAIL is intended to identify most situations in New Zealand where hazardous substances could cause, and in many cases have caused, land contamination. Read more about HAIL sites in Nelson here.
Copies of all the latest report and information that Council holds on hazards are available to read at any of the libraries in Nelson, Tahunanui and Stoke or available to download below.
- Tonkin & Taylor August 2013 Maitai River Flood Hazard Mapping modelling Report (13MB PDF)
- Revised Preliminary Assessment of the Liquefaction Hazard in Tasman and Nelson, February 2013 – desktop study (6.4MB PDF)
- Tonkin & Taylor November 2013 Tahunanui Area Liquefaction Assessment (37MB PDF)
Please note these are large files and may take a while to download or open. To save a copy to your desktop, right click the link and choose "Save link as...."
- Download the Maitai River flooding general information sheet (138KB PDF)
- Download the Tahunanui area liquefaction assessment general information sheet (136KB PDF)
- Download the Hazardous Activities and Industries List general information sheet (138KB PDF)
- Download the overview map (3.1MB PDF)
- Download the Suitably Qualified and Experienced Practitioner (SQEP) List: Soil Contamination Assessments (23KB PDF)